Backing-forming instrument for teeth.



J. S. MCDONALD. BACKING FORMING INSTRUMENT FOB. TEETH.

APPLICATION FILED JUNE 22, 1910.

Patented June 20, 1911.

2 SHEETS-SHEET 1.

J. S. MCDONALD. BACKING FORMING INSTRUMENT FOR TEETH. APPLICATION FILED JUNE 22, 1910.

Patented June 20, 1911.

JOSEPH s. MCDONALD,

ITED STATEb AT FFTQE.

OF COLUMBUS, OHIO.

BACKING-FORMING INSTRUMENT FOR TEETH.

Application filed June 22," 1910. SerialNo. 568,287.

To all whom it may concern:

Be it known that I, JOSEPH S. MCDONALD, a citizen of the United States, residing at Columbus, in the county of Franklin and State of Ohio,have invented certain new and useful Improvements in Backing-Forming Instruments for Teeth, of which the following is a specification.

This invention relates to new and useful improvements in backing forming instruments for teeth.

The primary object of this invention is to provide an instrument of this kind by means of which the individual dentist may very readily and easily construct the backing from a single sheet or strip of metal, preferably gold, and at a considerable saving in ex ense.

\Vith the foregoing and other objects in view, the invention consists in the novel features of construction, combination and arrangement of parts illustrated in the drawings and more particularly pointed out in the. appended claims.

i In theaccompanying drawings, Figure 1 is a perspective view of the instrument, with the secondary clamping jaw in normal or raised position. Fig. 2 is a similar view, with the secondary clamping jaw. closed. Fig. 3 is a plan view of the instrument with the handles partly broken away. Fig. 4C is a central longitudinal section, taken on the plane indicated by the dotted lines44 of Fig. 3, the movable secondary clamping jaw closed. Fig. 5 is a similar view, the movable secondary c-lamping jaw raised. Fig. 6 is a transverse section, taken on the line 66 ofFig. 3. Fig". 7 is a similar View, taken on the line 77 of Fig. 5. Fig. 8 is a horizontal section, taken on the line 8-8 of Fig. 4, and Fig. 9 is a general view, showing the diiferent steps in the process or operation of makingthe backing.

Referring to the drawings for a more particular description of the invention and which are for illustrative purposes only and are therefore not drawn to scale, the device comprises a pair of pivoted handle members 1, provided at their, inner ends with the main clamping jaws 2 and 3, the latter of which is some-what longer than the former.

The I device further comprises the secondary clamping jaws 4 and 5 the former being stationary and formed by suitably recessing the inner faceand'upper edge ofthe jaw 2,- as at 6, and the latter being formed tages of this invention pendedclaims.

by a movable spring retracted bar 7 The springs 8 for normally holding the movable jaw 5 in retracted or raised position are disposed around guide pins or studs 9, project ing from the upper edge of the secondary stationary jaw 4: into guide apertures 10 formed in the movable secondaryjaw 5. The upper ends of the springs seat in recesses 11 formed in the bottom edg'e of the jaw 5 directly beneath and in concentric relation with the apertures 10.

The instrument is further provided with three separate pairs of coincident or registering grooves A, B and C, the grooves A being'formed in the inner faces and near the bottom edges of the main jaws Qand 3, the grooves B in the inner faces and near the inner ends of the main jaws transversely thereof,or atright angles with the grooves A and the grooves G in the meeting or adjacent edges of the stationary jaws 4 and 5.

In constructing the backing, the main clamping jaws 2 and 3 are opened with the secondary clamping jaw 5 closed and the ends of the single fiat strip of gold or other metal from which the backing is formed pressed together over a small gage wire 0 arranged at the center of the strip, as shown at b, which forms the tubular portion 6 at the center of the strip, as shown at d. In closing the jaws to form the tubular portion 6, the sides of the metal forming said portion are pressed into transverse grooves B. After the tubular portion a is thus formed, the gage wire 0 is then withdrawn, the main jaws again opened, the tubular portion 6 of the blank then clamped in the grooves C, of the secondary clamping jaws, and the ends of the metal spread out fiat, as shown atg, by again closing the main jaws. The movable secondary clamping jaw 5 is moved into clamping position against the action of the springs 8-by the cam lever 12, pivoted as at 13, to the lug or bearing portion 14 of the main jaw 2. I

From the foregoing description taken in connection with the drawings, it is thought that the construction and operation of the invention will be readily understood without requiring a more extended explanation. Various changes in the form, proportions and minor details of construction may be resorted to without departing from the principle or ,sacrificing any of the advanas defined in the ap- Having deseribed'the invention, what I claim as new is,

l. A backing forming instrument ofthe class c eseribed comprising a pair of pivoted handle members provided at their inner ends with clam-ping jaws, a ,pair of relatively fixed and movable secondary clamping jaws, carried by one of the main jaws, the main and secondary jaws having pairs of co-incident grooves.

2. A backingvforming instrument of the class described comprising a pairof pivoted handle members provided at their inner ends with main clamping jaws having longitudinally and t'ansversely disposed co-incident grooves, a relatively stationary clamping jaw formed on one of the .main jaws, a spring retracted movable secondary jaw arranged forcooperation with said last mentioned jaw, and means for moving and hold ing the movable secondary jaw in clamping engagement with the fixed secondary jaw,

1 v i the fixed and movable secondary clamping jaws having co-incident grooves.

3. A backing forming instrument of the class described comprising a pair of pivoted handle members provided at their inner ends with main clamping gitudinal and transverse co-ineident grooves, a relatively stationary secondary clamping jaw formed on one of the main jaws, a spring retracted secondary clamping awarranged for cooperation with the said last mentioned jaw, a cam lever for moving and holding the movable secondary jaw in clamping engagement with the stationary secondary jaw, the stationary and. movable clamping jaws having co-incident grooves.

In testimony whereof I afiix my signature in presence of two witnesses.

JOSEPH s. MCDONALD.

Witnesses F. M. GLICK, B.-F. CURRAN.

jaws, having lon- 

